Mixing speeds of MOBO Processor and RAM

[kburkhart84]

OKAY. This is my first post. I'm not intending on this being my build, rather I just was thinking about just how cheap can you go when building a computer? I got together a complete build on newegg.com parts and came across an issue. Just remember that these parts are of the cheapest and that I'm not intending to build this way, but rather seeing what can be combined with what. The motherboard supports an FSB of 1333Mhz or 1066Mhz, and the "Memory Standard" is DDR2 800. First part I'm not sure about is why the slower ram and faster FSB support. The processor is a 2.2Ghz Core 2 Duo with FSB 800Mhz. The RAM was a single stick of PC2 6400(DDR2 800). I understand that if the RAM and Processor speeds don't match, than one will slow down to match the other, essentially wasting money, except for the possible upgrades later. So if my ram is DDR2 1066, and the processor is FSB 800, then the RAM will slow down to the same 800 speed. What I don't understand is how limiting the MOBO's specs are when they say the FSB support of 1333 and 1066. In other words, can it be any slower than those two or is limited to that. So if I were to put my FSB 800Mhz processor in their, would the MOBO itself slowdown, or would it not work? And why is the Memory standard slower than the FSB of the MOBO itself? Thanks in advance first for reading my long post and for any help you can give in understanding. Thank you.

[The Wise Monkey]

I think you are getting confused between the CPU and the RAM specifications. The FSB is related to practically everything, which is why it is usually the highest. The motherboard specs will say what speed of RAM it supports, which is usually PC2-6400 at the moment. Any RAM faster than that e.g. PC2-8500 will just slow down to the 6400 speed.

RAM and CPU speeds don't affect each other, so you don't need to worry about that. If the motherboard has a FSB of 1333 MHz, then it will support any CPU up to that limit e.g. the E6750 has a FSB of 1333 as well, so this will run at full speed. If you put the E6750 into a motherboard with an FSB of 1066, then that is the speed that the CPU will run at.

Basically, your motherboard will not slow itself down - your components will. :)

[kburkhart84]

Thanks for that. And then, if I put in ram that isn't fast enough for the motherboard? I understand that the components will slow down to meet the speed of the MOBO, but what happens if the components aren't fast enough to atleat meet the speed of the MOBO??

[The Wise Monkey]

It doesn't matter - the component will run at its maximum speed and won't affect the speed of everything else. The motherboard is very backwards compatible, so it will accept any RAM speed as long as it is of the correct type e.g. DDR2.

If you combine two sticks of RAM that run at different speeds, however, then the faster stick will slow down to match the other one.

[kburkhart84]

so the processor slows down to meet the slower ram. ok. that also works with the processor too. I understand it I more efficient moneywise usually to keep the speeds close to the same since faster compnents cost more, but asuming I did it would it stil work with both processor and ram slower than the mobo specifications.

[iiiprimeiii]

:confused:

[shyster]

:confused: hahah

Okay I am going to try and take a crack at what you are asking.

processor has two factors that determine speed the FSB and the GHz. The FSB (front side bus), which determines how quickly it interacts with the motherboard, I believe. The GHz is how fast the processor actually runs.

To explain this you could have two processors both at 3GHz but with one at 1333FSB and the other at 1066FSB. Although they appear to be the same in terms of "speed" the one that has the higher FSB is faster.

The RAM works in conjunction with but seperatly from the CPU. It has its one memory size and one speed rating. The memory size determines how much information the chip can hold at any given time kind of like the way a hard drive holds information. The speed rating of the memory works similar to the FSB on the CPU it determines how quickly it interacts with the other parts of the computer.

All that said if it still even makes sense. If you had one of the new e8400 processors (3GHz, 1333FSB) and a cheap ram 2x1 (667MHz) they would both run at their own speeds, the processor at 1333 and the ram at 667. The ram would not reduce the speed of the processor to 667 directly. The problem with this though is that the ram bottlenecks the rest of the system. It would be like trying to fit twenty guys through a single door all at the same time, physically impossible, so they have to go one or two at a time.

Hopefully this answered your question, and even more hopefully I am actually correct in what I said. If I am not though feel free to correct me anybody who knows more about this than me.

[kburkhart84]

thanks for the reply. I understand about what the processor and ram is and how they work and what their specs mean. what im trying to ask basicly if the processor and the ram are slower than the motherboard, asuming that said processor IS supported on the motherboard, wil it work. so if the processor is an intel core 2 duo at 800 mhz fsb, and the motherboard specs say it supports fsb of 1066 wil it still works. basicly what it seems to me is that the spec for the mobo should really say MAX fsb instead of just the supported fsb. I understand the ram will synchronize with multiple sticks of different speeds. and I understand that if the processor or ram I faster than what the mobo supports then said components will slow down. but what if the mobo is faster than theram and processor, wil the mobo slow down(or let the components run at their own speed at least?)

[shyster]

It doesn't matter - the component will run at its maximum speed and won't affect the speed of everything else. The motherboard is very backwards compatible, so it will accept any RAM speed as long as it is of the correct type e.g. DDR2.

If you combine two sticks of RAM that run at different speeds, however, then the faster stick will slow down to match the other one.

I believe this was the answer to that question. The backwards compatibility means that it can support what is listed, but also things that have come before it, so if it says natively support 1333 or 1066, it should also support 800 as well. However you can always try calling the customer service or tech support of any company whos motherboard you are looking at and they should have a definative answer.

But like WM said, motherboards are very backwards compatible.

[kburkhart84]

ok. im just trying to make sure because the WM said that slower ram would work, but did not specify that a slower processor would work. thanks for the patience guys.

[iiiprimeiii]

ah ha!! i see what u were saying now! :D

[kburkhart84]

yeah. my grammer and sentence structure is better on a computer keyboard. my posts were mostly done on a pocket PC phone. :-)